Tex. Election Code § 232.006: VENUE.

(a) The venue of an election contest for a statewide office is in Travis County.

(b) The venue of a contest for an office less than statewide that is filled by voters of more than one county is:

(1) in the county in which the contestee or any one of the contestees named under Section 232.003 resides if the residence is in the territory covered by the election; or

(2) in any county wholly or partly in the territory covered by the election if:

(A) no contestee named under Section 232.003 resides in that territory; or

(B) none of the contestees is named under Section 232.003.

(c) The venue of a contest for an office filled by voters of only one county is in that county.

Acts 1985, 69th Leg., ch. 211, Sec. 1, eff. Jan. 1, 1986.